1. Field of the Invention
The present invention relates to a vehicle shock absorber in which a damper is housed in a space defined by an outer tube member and an inner tube member.
2. Description of the Related Art
There is a known vehicle shock absorber in which a damper is housed in a space defined by an outer tube member and an inner tube member that is disposed to the inside of the outer tube member and so as to be capable of relative movement in the tube axial direction. With this vehicle shock absorber, as disclosed in Japanese Laid-Open Patent Application 2003-148546, for example, an inner tube member is disposed to the inside of an outer tube member and so as to be capable of relative movement in the axial direction, and a coil spring is disposed between the outer tube member and the inner tube member. The interior space defined by the outer tube member and inner tube member is sealed. This allows any impacts that the vehicle receives from the road surface to be absorbed by an air spring within the internal space and the coil spring.
With the above-mentioned vehicle shock absorber, a damper is provided in the internal space defined by the outer tube member and inner tube member. The damper includes a damper cylinder that is connected to the outer tube member and is filled with oil, and a piston rod that is connected to the inner tube member and includes at its distal end portion a piston that moves relatively within the damper cylinder. With this configuration, when the piston moves within the damper cylinder along with the relative movement of the outer tube member and inner tube member, a damping force is produced by oil flowing through a port provided in the piston.
When the vehicle shock absorber disclosed in Japanese Laid-Open Patent Application 2003-148546 is used for the front fork of a motorcycle or the like, however, depending on how the motorcycle is being ridden, the vehicle shock absorber may not operate smoothly. Specifically, the vehicle shock absorber will operate normally as long as the motorcycle is being ridden normally over a road, but when the motorcycle is being ridden in a way that puts a great deal of stress on it, such as when the motorcycle is jumped and then makes a landing, the resistance inside the vehicle shock absorber may be so high that the vehicle shock absorber does not operate smoothly. One possible cause of this is that the guide member in the vehicle shock absorber comes into contact with the inner tube member.